The presently disclosed and/or claimed inventive concept(s) relates to a volumetric heating device that may be applied in a beverage or food preparation machine.
The volumetric heating device is especially designed to heat a liquid, used in the beverage or food preparation process, in particular in beverage or food dispensing machines such as coffee, tea, or soup automats.
It is well known that microwaves can be used for volumetric heating of a liquid. For example, a liquid, e.g. water, fat, and other substances absorb energy from emitted microwaves in a process called dielectric heating. Many molecules (such as those of water) are electric dipoles, meaning that they have a partial positive charge at one end and a partial negative charge at the other, and therefore rotate as they try to align themselves with the alternating electric field of the microwaves. Rotating molecules hit other molecules and put them into motion, thus dispersing energy. This energy, when dispersed as molecular vibration in solids and liquids (i.e., as both potential energy and kinetic energy of atoms), is heat. Volumetric heating hence differs from conventional heating methods and means that energy is directly conveyed to the molecules of the liquid without requiring a heat exchanger.
However, microwave heating devices are often complex devices and are also expensive. A microwave heating device, e.g., may comprise a high voltage power source, commonly a simple transformer or an electronic power converter, which passes energy to a magnetron, a high voltage capacitor connected to the magnetron. The device needs the magnetron itself, which converts high-voltage electric energy to microwave radiation, and also requires a magnetron control circuit (usually with a microcontroller). Further, a waveguide (to control the direction of the microwaves) and a cooking chamber, commonly formed of a conductive material and built similar to a faraday cage to prevent the microwaves from leaving the cooking chamber are essential parts.
While microwave heating devices such as microwave ovens are available on the market to the customer for relatively low prices, an application in beverage or food preparation devices is often complicated due to technical and safety requirements, but also due to the room required for such application.
In turn, the price of generally relatively simple beverage or food preparation devices would be drastically increased by application of such microwave heating devices.
It is therefore an aim of the presently disclosed and/or claimed inventive concept(s) to provide an alternative to a microwave heating device which can be easily and safely used, for example in a catering environment, and which can be easily implemented in beverage or food preparation machines requiring that a liquid is heated. Also, the room needed for application of the inventive heating device is considerably lower than for known heating devices.
The presently disclosed and/or claimed inventive concept(s) provides a solution to these problems as claimed with the independent claims. Further beneficial aspects of the presently disclosed and/or claimed inventive concept(s) are subject to the dependent claims.